The invention relates to a method for electro-optically scanning, especially for photographically imaging cubic or cuboid articles such as cigarette packs, with at least one inspection means (camera) arranged obliquely relative to the pack to be scanned. The invention further relates to an apparatus for electro-optically or photographically scanning cubic or cuboid articles.
Packs, especially cigarette packs of the hinge-lid type, are very thoroughly checked in the region of the packaging machine as regards correct structure. Recently, this check comprises a photographic inspection with the aid of fixedly installed cameras which detect the outer faces of the pack. The images produced therewith are compared to standard images. In the case of undesired variations of the external appearance, the defective packs are rejected.
Systems for electro-optically scanning (cigarette) packs are designed such that one or two cameras detect, i.e. produce an image of as many outer faces of the packs as possible while the packs are being transported. In a known apparatus (DE-A-38 01 388), the cuboid cigarette packs rest on their (large-surfaced) front panel while they are transported on a conveyor belt to which suction air is admitted. The free rear side and two adjoining faces can be detected by a camera arranged next to the transport path of the packs. A first conveyor belt is follwed by a second conveyor belt to which suction air is admitted as well and which engages the pack on the opposite side. A second camera can then detect the faces of the pack which are now exposed.
This known system has a relatively complicated structure. The conveyor belts to which suction air is admitted require an increased and permanent expenditure of energy.